Method of controlling rolling apparatus

Abstract

A method for controlling a rolling apparatus in which heated materials are successively extracted from heating ovens to be rolled with rollers and each extracting interval time between the materials is controlled such that the maximum root mean square valve of power supplied to motors for driving the rollers is less than the permissible root mean square power valve of the driving motors in any one of the rolling passes.

What is claimed is: 
     
       1. A method of controlling extractor means and roller means of a rolling apparatus such that heated materials are successively taken out from heating means and fed to a transport table at a predetermined time interval by said extractor means and rolled to a predetermined thickness by said roller means through a plurality of rolling passes providing respective predetermined gaps, comprising the steps of: obtaining the root mean square value of electrical power supplied to motor means for driving said roller means during each of said rolling pass; and   correcting said interval at which the materials are successively taken out by said extractor means by setting this interval to an amount such that the maximum root mean square value of the power supplied to said motor means is less than the permissible root mean square power value of said motor means in any one of the passes.   
     
     
       2. The method of control according to claim 1, wherein said root mean square value of power is given as ##EQU7## wherein t is time, τ is the time duration between the start of rolling in an i-th pass and the start of rolling in an (i+1)-th pass, and I oi  is the rated current of said motor means for the i-th pass. 
     
     
       3. The method of control according to claim 2, wherein the amount of correction of said interval is given as ##EQU8## wherein I RMSO  is the maximum permissible root mean square value of power supplied to said motor means in any one of the passes. 
     
     
       4. A method of controlling extractor means and roller means of a rolling apparatus such that heated materials are successively taken out from heating means and fed to a transport table at a predetermined time interval by said extractor means and rolled to a predetermined thickness by said roller means through a plurality of rolling passes providing respective predetermined gaps, comprising the steps of: obtaining the minimum number of rolling passes by dividing the total required electrical power supplied to motor means for driving said roller means by the maximum permissible rolling power for said roller means in any one of the passes;   calculating rolling speed and backward motion start timing of said roller means corresponding to selected minimum rolling time;   obtaining the root mean square value of power required for rolling for said selectable rolling time; and   correcting idle time of said roller means such that said root mean square value of the required power is less than the required root mean square power value of said motor means in any one of the passes.   
     
     
       5. The method of control according to claim 4, wherein said root mean square value of required power is given as ##EQU9## wherein KW Ri  is the power required for rolling in an i-th pass, KW Ii  is the power required during the time between the end of rolling in the i-th pass and the start of rolling in an (i+1)-th pass, τ Ri  is the time required for rolling in the i-th pass, τ Ii  is the idle time in the i-th pass, and P is the number of passes involved.